With the advent of new technology in the optical cable field, the use of optical fiber cables has greatly increased. New telephone lines comprised of a number of optical cable fibers are integrated into lines carrying over one hundred and eighty different optical fibers each. Each line is encased with other lines until a large optical cable has been produced. Since the optical fiber is brittle any sagging or sharp bending in the line could cause the line to break. Because of the great importance to the communications industry of the optical cable itself, these cables are Federally protected. When they are exposed, it is not infrequent that an armed guard will be used to protect the cable. When other utilities need to dig under or around this large optical cable, many precautions are taken. An inspector is often kept at the site of the digging until the construction is completed. Additionally, special equipment may be needed to support the exposed cable to insure that it does not bend excessively, breaking the fibers inside the cable. If a cable breaks, it could cost the communications industry as much as $70,000.00 for each minute that the large optical cable is in a non-functioning condition. Digging under these cables creates a problem in that the cable should never bend or sag under its own weight.
There are several types of encasement devices used to help support the optical cables when they are exposed. One such device involves the use of a plastic or metal case which is essentially circular and which is hinged at the bottom. One hundred and eighty degrees from this hinge the case is cut and upper flanges are put on each semi-circular half. The cable may then be encased by the plastic or metal which is joined by bolts on the upper flange. To connect a number of pieces, a circular collar is bolted onto adjoining ends of the tubing. However, problems arise in the circular tubing connections. Oftentimes the collar does not fit tight enough and cannot be tightened so that a number of lengths of tubing can be connected to support the optical cable over a long distance. The very nature of plastic also makes it less advantageous when used in the above manner.
Another type of tubing has also been used for encasing the optical cable. This tubing is cut longitudinally down its length. The tubing may be forced open in order to encase the optical cable. However, the cable currently in use is very difficult to open and will often spring open or spring shut, causing a dangerous condition to occur to the workmen. Additionally, the method used to cut the tubing (whether sawing or other methods) produces heat which in turn can create warpage in the tubing. The warpage not only makes the tubing act like a spring when it opens, it can also distort the linearity of the tubing, thus causing bends in the length of the optical cable.
In most applications of encasement of optical fiber cable, the casing is left on permanently so that the valuable optical cable is protected. In certain trouble areas, for example ground washouts or where there are other utility lines present, it is a common practice to leave the casing to protect the optical cable and reduce the risk of the cable being broken or otherwise damaged.
There has been a long-felt need in the communications industry to develop a means for encasing optical fiber cable. This casing should be strong enough to permanently protect the cable, yet should be designed so that it may be easily and quickly installed around the optical fiber cable in need of protection. There is further a need to provide lengths of casing which may be securely attached to each other so that they can support the optical fiber cable over an expanse of distance frequently encountered in repair work.
It is an object of this invention to provide a casing for an optical fiber cable which is strong enough to support the cable over a long distance. It is also an object of this invention to provide a casing for a fiber optical cable which is easily and quickly installed and which causes no danger to the workman in the installation procedure.
It is a further object of this invention to provide a casing for fiber optical cable which may be rapidly deployed as the emergency need arises. Other and further objects of this invention will become obvious upon reading the following Specification.